1. Field of the Invention
This disclosure relates to implantable monitoring devices, and implantation systems and methods for implanting the monitoring devices at a subcutaneous implant location.
2. Prior Art
Implantable devices that monitor cardiac physiologic activity are frequently implanted subcutaneously under a patient's skin in the chest. An implantable loop recorder (ILR) is an example of a device that may be implanted in this fashion. The exemplary ILR 10 shown in FIG. 1 is shaped like a small pacemaker. The ILR comprises a housing 12 for the device electronics and battery power source. A header 14 is supported on the housing and contains conductors connected to the device electronics through one or more hermetic feedthroughs. An antenna 16 extends outwardly from a header 14. This device can be used to record an electrocardiogram (EGG) signal for the patient.
To implant the ILR device, a 25 mm incision is made, a subcutaneous pocket is formed near the incision, and a tunnel is formed to extend away from the pocket for placement of the flexible lead using a tool or finger. The ILR device may be inserted through the incision and placed in the subcutaneous pocket, tested for proper operation, and repositioned if necessary. The incision is then closed.
Implanting ILR devices in this manner may be difficult, especially for physicians who are not skilled in device implantation. If the ILR device is improperly implanted, undesirable complications for the patient or suboptimal device performance may result. In addition, tearing of tissue during formation of the pocket and tunnel, for example, may result in tissue bleeding that requires appropriate steps during surgery to avoid hematoma. In addition, it may be necessary to employ fluoroscopy to assure that the antenna is properly positioned under the skin. If not properly positioned, the ILR and antenna may require repositioning to obtain an optimal EGG signal. This may extend the surgery duration, which may increase risk of infection and trauma, as well as expense.
Accordingly a need exists for an improved insertion system for a simpler approach to insertion, shorter insertion time, reduced risk of complications, reduced expense, and a reduced need for expensive equipment, such as fluoroscopy, during device placement.